Valve and valve control for preventing passage of processed material to blower for pyrometer sight passage on a rotary kiln



A. v. BARON 3,515,379 VALVE AND VALVE CONTROL FOR PREVENTING PASSAGE OFJune 2, 1910 PROCESSED MATERIAL TO BLOWER FOR PYROMETER SIGHT PASSAGE ONA ROTARY KILN Original Filed Jan. 25, 1968 COUNTER AC TO DC CONVERTER Tw/T AC SOURCE INVENTORS. ANTHONY v BARON HUGH s. DREWRY JOHN N. LEES,JR.c. M

United States Patent 3,515,379 VALVE AND VALVE CONTROL FOR PREVENT- INGPASSAGE OF PROCESSED MATERIAL TO BLOWER FOR PYROMETER SIGHT PASSAGE ON AROTARY KILN Anthony V. Baron, South Milwaukee, and Hugh S. Drewry andJohn N. Lees, In, Wauwatosa, Wis., assignors to Allis-ChalmersManufacturing Company, Milwaukee, Wis.

Continuation of application Ser. No. 700,410, Jan. 25, 1968. Thisapplication June 11, 1969, Ser. No. 845,594 Int. Cl. F271) 7/00 US. Cl.26333 16 Claims ABSTRACT OF THE DISCLOSURE A combined pyrometer andsight passage or tube for a rotary kiln or the like including a blowerfor supplying forced air to the sight tube and a valve member, which maybe in the form of a sliding vane or the like actuated by anelectromechanical operator, interposed in the duct connecting the blowerto the sight tube, or in the sight tube. The valve member is moved toclosed position in response to detection of a predetermined diminishedair flow from the blower. Suitable timing devices are provided to openthe valve a predetermined interval of time after the closing of thevalve to determine whether the blockage in the air path has beenremoved. A counting device is provided to count the number of closuresof the valve in response to the dimnished air flow condition and after apredetermined count has been reached, to actuate the valve to a closedposition until the condition has been corrected and the counter has beenreset.

This is a continuation of application Ser. No. 700,410, filed Jan. 25,1968, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to temperature measurement in rotary kilns, and moreparticularly to a valve and valve control arrangement for preventingpassage of the material being processed to the blower which provides aforced air supply to the pyrometer sight passage or tube.

DESCRIPTION OF THE PRIOR ART This invention may be considered animprovement on the disclosure of US. 3,345,873 issued to Otto G. Lellepon Oct. 10, 1967, entitled Rotary Kiln Temperature Measurement. In thedisclosure of the Lellep patent, a radiation pyrometer is mounted on theoutside of the kiln shell in an enlarged section of duct work whichconnects to an air blower and also to a sight passage extending throughthe kiln shell. The air stream supplied by the blower in the Lelleppatent passes through the duct work and through the sight passage intothe inside of the kiln and in so doing helps to keep the sight passagefree from processed material, dust and combustion gases, and at the sametime, helps protect the pyrometer from becoming overheated.

In the Lellept construction, despite the fact that the blower isproviding an air stream through the duct work connected to the sightpassage or tube, there is still the possibility that some of thematerial being processed may find its way into the duct work andeventually reach the blower where it will cause clogging of the blowerand consequent interruption of the air supply to the sight passage.

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SUMMARY OF THE INVENTION Accordingly, it is an object of the presentinvention to provide in combination with a pyrometer and sight tubehaving a forced air supply from a blower or the like a movable valvemember and control therefor which prevents passage of material beingprocessed to the blower.

It is another object of the invention to provide in combination with apyrometer and sight tube for a rotary kiln or the like a control systemand apparatus for detecting a diminished flow of air from the blower tothe sight tube and for initiating appropriate corrective action.

It is another object of the invention to provide in combination with apyrometer and sight tube assembly having a forced air supply from ablower or the like, a means for isolating the blower from the materialbeing processed whereby to prevent entry of the material being processedinto the blower with resultant clogging of the blower.

In achievement of these objectives, there is provided in accordance withthis invention a combined pyrometer and sight passage or tube for arotary kiln or the like including a blower for supplying forced air tothe sight tube and a valve member, which may be in the form of a slidingvane or the like actuated by an electromechanical operator, interposedin the duct connecting the blower to the sight tube, or in the sighttube. The valve member is moved to closed position in response todetection of a predetermined diminished air flow from the blower.Suitable timing devices are provided to openl the valve a predeterminedinterval of time after the closing of the valve to determine whether theblockage in the air path has been removed. A counting device is providedto count the number of closures of the valve in response to thediminished air flow condition and after a predetermined count has beenreached, to actuate the valve to a closed position until the conditionhas been corrected and the counter has been reset.

Further objects and advantages of the invention will become apparentfrom the following description taken in conjunction with theaccompanying drawing in which the sole figure is a view in sectionshowing a pyrometer and sight tube assembly mounted on a rotary kiln orthe like and connected to an air projecting means such as a blower, andfurther schematically showing the valve which can be moved to close theduct leading to the blower to prevent passage of the processed materialto the blower, together with the control circuit which controlsactuation of the movable valve member.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing,there is shown a rotary kiln generally indicated at 10 which may begenerally similar, for example, to the rotary kiln shown in the US. Pat.2,728,146, issued to Benjamin L. Cody, on Dec. 27, 1955. Reference isalso made to US. Pat. 3,273,874, issued to Ernest Hucke on Sept. 20,1966, for a showing of a typical kiln used in cement manufacturing. Therotary kiln includes an outer shell 12 and a refractory wall 14. Thepyrometer and sight tube assembly is generally indicated at 16 andcomprises a sight tube 18 which extends through a passage 20 in the kilnwall. The sight tube 18 projects radially outwardly beyond the outershell 12 of the kiln and is provided at/ its radially outermost end witha flange 22 on which a radiation pyrometer generally indicated at 23 ismounted.

In the illustrated embodiment, the radiation pyrometer 23 is open at theradially inner end thereof adjacent flange 22, and a lens 24 is suitablymounted in the open end of the pyrometer to close the opening. Radiantenergy which reaches lens 24 through sight tube 18 is focused by thelens onto temperature sensing element 25 of the pyrometer. The signal ofsensing element 25 is conducted to an external control circuit throughconductors 26 which are attached to slip rings on the outer surface ofthe kiln, the slip rings engaging brushes connected to the externalcircuit. It will be understood that the illustrated pyrometer is shownby way of example only and that other forms or types of pyrometers maybe used.

For purposes of this application, a radiation pyrometer is herebydefined as a temperature sensitive instrument which will measure thetemperature of an object or substance at a distance without makingphysical contact with the object or substance.

An air projecting means in the form of a blower 27 driven by an electricmotor 28 is suitably mounted on the outer wall 12 of the kiln. Blower 27is connected by a duct 29 to the interior of the sight tube 18. Inaccordance with the invention, a valve member generally indicated at 30is interposed in the air flow path between the kiln and the blower 27and more specifically, in the illustrated embodiment, in the duct 29between blower 27 and the connection of duct 29 to the sight tube 18. Inthe illustrated embodiment, the valve 30 is in the form of a slideablymovable vane having an aperture 31 therein which may be moved into orout of registration with the passage in duct 29. When the sliding valve30 is in a position in which the aperture 31 therein is in registrationwith the passage in duct 29, the valve 30 is in open position, whereaswhen the sliding vane is moved to a position in which the aperturetherein is completely out of registration with the passage in the duct29, the valve is then in closed position.

In the region where the slideable vane moves across the duct 29, theduct is interrupted to provide a slot through which the slideable vanemay move, this slot lying between the flanges 33 provided on thecontiguous duct portions. Suitable spacers, not shown, may be providedbetween the contiguous flanges 33 to guide the movement of the slidingvane.

Valve 30 is moved to either a completely open or a completely closedposition by a suitable electromechanical operator which in theillustrated embodiment is shown as a solenoid 32 which acts upon aplunger 34 or the like of magnetic material suitably connected to theslideable vane valve 30.

In accordance with the invention, the air flow in duct 29 from theblower to the sight tube 18 is sensed by a pivotally movable vane 36,since a substantial decrease in air flow is an indication of a blockageof duct 29 and/ or sight tube 18 due to the presence of foreign materialin the sight tube 18 leading to the duct 28. A control circuit isprovided which responds to detection by vane 36 of a predetermineddiminished air flow to close sliding vane valve 30 by moving valve 30 toa position in which the aperture therein is not in registration with thepassage in duct 29. Sensing vane 36 is pivotally mounted at point 38 andhas attached thereto a switch contact 40. Under normal air flowconditions in duct 29, vane 36 is in the position shown in the drawingin which contact 40 is in open position. A spring 42 is provided andnormally biases contact 40 toward the circuit closing position. However,the pressure exerted by the air flow on vane 36 is normally sufficientto overcome the biasing pressure of spring 42 and maintain contact 40 inopen position.

The contact 40 operated by the air flow responsive vane 36 iselectrically connected in series with a timing device generallyindicated at T across an alternating current power supply derivedthrough slip rings 43 carried by the kiln. Slip rings 43 are connectedthrough brushes 44 to an external source of alternating current power. Asecond timing device T is connected in electrically parallel relation totimer T Timers T and T may be of the type manufactured by Eagle SignalCompany, of Moline, 111., under the designation HPS Series Cycl-FlexReset Timer, as described in Bulletin 125, dated April 1962, publishedby Eagle Signal Company.

A pulse operated counting device 45 is also electrically connected inparallel with timers T and T Counter 45 may be of any suitable type andmay, for example, be of the type manufactured by Hecon Corp., of NewShrewsbery, N.]., under the designation Series FEO43- PredeterminingElectro Magnetic Counter, as described in Specification Sheet FEO43(undated but known by applicant to be available in 1966).

A normally closed contact 46, operated by timer T is connected in serieswith the vane operated contact 40 and is therefore also connected inseries with the parallel connected timers T and T and counter 45 to theAC. electrical power supply.

A normally open contact 47 operable to closed position by counter 45after a predetermined number of pulses have been applied to the counter,is connected in electrically parallel or shunting relation to the seriescon nected contacts 42 and 46.

Timer T operates a pair of movable contacts 48 and 49 which areconnected to the DC. output terminals 50 and 51 respectively, of an AC.to DC. converter or rectifier 52. The AC. input terminals 53, 54 ofconverter 52 are connected to slip rings 43. Contacts 48, 49 control theenergization circuit of the electromechanical operator such as thesolenoid 32 which selectively moves valve member 30 to either open orclosed position as will now be described.

Movable contact 48 is selectively movable by timer T into engagementwith either terminal 55 or 56 and movable contact 49 is selectivelymovable by timer T into engagement with either terminal 57 or 58.Terminals 55 and 58 are connected together by a jumper 60. Theelectromechanical operator such as solenoid 32 is provided with twoinput leads 62 and 64, respectively. Lead '62 is connected to terminal55 and, through jumper 59, to terminal 58 and, lead 64 is connected toterminal 56 and through jumper 60, to terminal 57.

When contacts 48 and 49 engage the terminals 55 and 57 as shown in thedrawing (corresponding to the deenergized condition of timer T solenoid32 is energized in a direction which causes sliding valve 30 to be in anopen position, whereas when contacts 48 and 49 engage terminals 56 and58 (corresponding to an energized condition of timer T solenoid 32 isenergized in a direction which causes valve 30 to be in a closedposition.

Timer T is constructed to provide a predetermined time delay after theenergization of timer T such as 5 seconds, before the contacts 48 and 49are moved into engagement with terminals 56 and 58 to cause a movementof valve 30 to closed position.

Timer T which is energized simultaneously with timer T is constructed toprovide a time delay, such as 10 seconds, after which timer T openscontact 46 to deenergize timer T and T When timers T and T aredeenergized, they automatically reset themselves to the conditionprevailing before their energization, in which (1) contacts 48 and 49operated by timer T are in engagement with terminals 55 and 57; and (2)contact 46, operated by timer T is in its normally closed position. Theresetting action just describde in well known in the timer art, and is acharacteristic of the aforementioned HPS Series Cycl-Flex Reset Timer,described in Bulletin 125, dated April 1962, published by Eagle SignalCompany, of Moline, Ill.

SUMMARY OF OPERATION Under normal air flow conditions in duct 29, vane36 is moved by the air How to a position in which contact 40 is open,and timers T T and counter 45 are thereby deenergized.

When the air flow in the duct 29 decreases a predetermined amount,indicative of a blockage in the air flow path comprising the duct, thebiasing action of spring 42 will cause the switch 40 to close and sincethe normally closed switch contact 46 in series with timers T and T isalready closed, timers T and T are energized. The closure of switch 40will also cause a counting pulse to be applied to counter 45. Timer Tafter a predetermined time delay, such as 5 seconds, will then moveswitch contacts 48 and 49 into engagement with terminals 56 and 58,respectively, which is just the reverse of the initial connection ofthese contacts, and which causes solenoid 32 to be energized in adirection which causes valve 30 to be closed.

Timer T which was energized simultaneously with the energization oftimer T begins to time a period of, for example seconds, at the end of'which timed period it opens contact 46 and thereby deenergizes bothtimers T and T As a result, contacts 48 and 49 return to the positionshown in the drawing in which contact 48 engages terminal 55 and contact49 engages terminal 57. This position of contacts 48 and 49 energizesthe electromechanical operator 32 to return the sliding vane 30 to theopen position in which the aperture 31 in the sliding vane is again inregistration with the passage of duct 29.

If the diminished air flow condition or blockage which caused theclosing of contact 40 has corrected itself before the end or at the endof the period timed by timer T contact 40 will open to deenergize thecircuits of timers T and T causing contacts 48 and 49 to move to aposition in which valve 30 is in open position. However, if thecondition causing the diminished air flow in duct 28 still persists,vane 36 will remain in a position in which contact 40 is closed and thetimers T and T will again be energized to repeat the cycle previouslydescribed. The counting device 45 is pulsed or indexed one position orstep each time timers T and T are energized. Upon a predetermined numberof actuations of the timer T such as three, for example, the normallyopen contact 47 will be closed to by-pass or shunt contacts 40 and 46.

Contact 47 controlled by counter 45 will when closed also actuate analarm or indicator 66 connected in parallel with timers T and T Thus,after the timers T and T have been repetitiously energized apredetermined number of times, which is indicative of a continuingblockage in the air flow path in duct 29 or in sight tube 18 the timer Twill remain continuously energized thereby, after an initial delay, suchas 5 seconds, causing contacts 48 and 49 to move into engagement withterminals 56 and 58 in which the polarity connections of theelectromechanical actuator 32 are such as to move the sliding vane 30 toa closed position in which the aperture 31 thereof is out of registrywith the passage in dust 29. Timer T will also remain continuouslyenergized and after an initial predetermined delay interval such as 10seconds, will open contact 46. However, the opening of contact 46 willbe ineffective to deenergize timers T and T due to the fact thatcontacts 42 and 46 are now shunted by colsed contact 47. Contact 46 willremain open until the circuits of timers T and T are deenergized by theresetting of counter 45.

After counter 45 has closed contact 47, as just described and the alarmor indicator 66 has been energized, the kiln operator is put on noticethat a blockage problem exists in the duct 29 or in sight tube 18 whichis preventing proper air flow to the sight tube, and which also maypermit the passage of material to blower 27 which could clog the blower.The kiln operator may then take ap propriate action to remove theobstruction, after which he shound reset the counter to its zeroactuated position. Resetting of the counter 45 will cause switch 47 toopen, with consequent deenergization of signal or alarm 66. Opening ofcounter operated switch 47 will remove the shunt across contacts 40 and46. Since, if the cause of the air flow blockage has been removed,contact 40 shound be in open position, the circuits of timers T and Twill be deenergized, and valve 30 is consequently in open position.

It can be seen from the foregoing that there has been provided inaccordance with this invention an apparatus for use in combination withrotary kilns or the like which senses a reduction in the air flow fromthe blower to the pyrometer sight tube, and closes a valve in the airflow path to prevent passage to the blower of the material beingprocessed, thereby preventing clogging of the blower.

While there has been shown and described a particular embodiment of theinvention, it will be obvious to those skilled in the art that variouschanges and modifications may be made therein Without departing from theinvention and, therefore, it is aimed to cover all such changes andmodifications as fall within the true spirit and scope of the invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In combination, a rotary kiln through which a material passes whilebeing heated to elevated temperature, means forming a passage throughthe wall of the kiln, a pyrometer mounted on the outside of the kiln forrotation therewith and aligned with said passage to receive radiationfrom the kiln interior through said passage, air projecting means inpneumatic communication with said passage for projecting an air streamthrough said passage into the kiln, a valve means interposed in the pathof air fiow provided by said air projecting means, means for sensing airflow from said projecting means, and means for controlling the positionof said valve means in response to the sensed air flow.

2. The combination defined in claim 1 comprising an electromechanicaloperator for said valve means, and control means responsive to air flowin said path for causing said operator to open said valve means when airflow is normal and to close said valve means when air flow is apredetermined value less than normal.

3. The combination defined in claim 1 in which said air projecting meansis a blower.

4. The combination defined in claim 1 comprising an electromechanicaloperator for said valve means, a sensing element positioned in the pathof air flow to sense air flow in said path, and control means actuatedby said sensing element for causing said operator to o en said valvemeans when air flow is normal and to close said valve means when airflow is a predetermined value less than normal.

5. The combination defined in claim 1 comprising an electromechanicaloperator for said valve means, a sensing element positioned in the pathof air flow to sense air flow in said path, control means actuated bysaid sensing element comprising timing means, said timing means beingactuated upon detection by said sensing element of a predetermineddiminution in air flow, said timing means being effective upon actuationthereof to maintain said valve means in closed position for apredetermined time and at the end of said predetermined time to reopensaid valve means.

6. The combination defined in claim 5 comprising a counting meansconnected to said timing means and effective to count the number ofactuations of said timing means, an electrical energization circuit forsaid timing means including a switch contact operated by said air flowsensing element, and shunting contact means operated by said coutingmeans, said shunting contact means being operated into closed electricalshunting relation to said switch contact operated by said air flowsensing element whereby to maintain said electromechanical operator in aposition in which said valve means is closed until said counting meansis reset to open said shunting contact.

7. The combination defined in claim comprising a counting meansconnected to said timing means and effective to count the number ofactuations of said timing means, and means actuated by said countingmeans upon reaching a predetermined count to cause saidelectromechanical operator to maintain said valve means in closedposition until said counting means has been reset.

8. The combination defined in claim 1 comprising an electromechanicaloperator for said valve means, a sensing element positioned in the pathof air flow to sense air flow in said path, control means actuated bysaid sensing element comprising a first timing means and a second timingmeans, an electrical energization circuit for said first and secondtiming means including a switch contact operated by said air flowsensing element, said first timing means being effective when in oneenergization state corresponding to a sensed diminished air flowtoactuate said electromechanical operator to close said valve means andwhen in the opposite energization state corresponding to a sensed normalair How to actuate said electromechanical operator to open said valvemeans, and normally closed electrical contact means operated by saidsecond timing means and operable by said second. timing means after apredetermined interval of closure of said valve means to cause areversal in the energization state of said first and second timingmeans, whereby to cause resetting of said first and second timing meansand opening of said valve means.

9. The combination defined in claim 8 including a counting means, meansfor applying counting pulses to said counting means indicative of thenumber of actuations of said first and second timing means, and meansoperated by said counting means after having a predetermined number ofcounting pulses applied thereto for causing said electromechanicaloperator to maintain said valve means in closed position until saidcounting means has been reset.

10. An apparatus for use with a rotary kiln of the type having a passagethrough the wall of the kiln adapted to be in pneumatic communicationwith a source of air supply and with the interior of said kiln to definean air flow path from said source to the interior of said kiln}comprising a valve means interposed in the air fiow path, means forsensing air how in said path, and means for controlling the position ofsaid valve means in response to the sensed air flow.

11. The apparatus defined in claim 10 comprising an electromechanicaloperator for said valve means, and

8 control means responsive to air flow in said path for causing saidoperator to open said valve means when air flow is normal and to closesaid valve means when air flow is a predetermined value less thannormal.

12. The apparatus defined in claim 10 in which said source of air supplyis a blower.

13. The apparatus defined in claim 10 including a pyrometer mounted onthe outside of the kiln for rotation therewithand aligned with saidpassage to receive radiation from the kiln interior through saidpassage.

14. The combination defined in claim 10 comprising an electromechanicaloperator for said valve means, a sensing element positioned in the pathof air flow to sense air How in said path, and control means actuated bysaid sensing element for causing said operator to open said valve meanswhen air flow is normal and to close said valve means when air flow is apredetermined value less than normal.

15. The combination defined in claim 10 comprising an electromechanicaloperator for said valve means, a sensing element positioned in the pathof air flow to sense air flow in said path, control means actuated bysaid sensing element comprising timing means, said timing means beingactuated upon detection by said sensing element of a predetermineddiminution in air flow, said timing means being effective upon actuationthereof to maintain said valve means in closed position for apredetermined time and at the end of said predetermined time to reopensaid valve means.

16. The combination defined in claim 15 comprising a counting meansconnected to said timing means and effective to count the number ofactuations of said timing means, and means actuated by said countingmeans upon reaching a predetermined count to cause saidelectromechanical operator to maintain said valve means in closedposition until said counting means has been reset.

References Cited UNITED STATES PATENTS 2,275,265 3/1942 Mead. 3,039,5226/1962 Scholl. 3,345,873 10/1967 Lellep 26333 X 3,379,062 5/1968 Lellep.

JOHN J. CAMBY, Primary Examiner U.S. Cl. X.R. 73-351

